/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.tez.util;

import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class TezRuntimeShutdownHandler {
  private static final Logger LOG = LoggerFactory.getLogger(TezRuntimeShutdownHandler.class);

  private static final List<Runnable> shutdownTasks = new ArrayList<>();

  private TezRuntimeShutdownHandler() {
  }

  public static void addShutdownTask(Runnable r) {
    shutdownTasks.add(r);
  }

  public static synchronized void shutdown() {
    LOG.info("Handling {} shutdown tasks", shutdownTasks.size());
    for (Runnable shutdownTask : shutdownTasks) {
      shutdownTask.run();
    }
  }
}
